Dresden 2009 – scientific programme
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DS: Fachverband Dünne Schichten
DS 26: Poster II
DS 26.13: Poster
Wednesday, March 25, 2009, 09:30–12:30, P5
Multilayers as optical elements for X-ray microscopy — •Tobias Liese, Andreas Meschede, and Hans-Ulrich Krebs — Institut für Materialphysik, Universität Göttingen, Friedrich-Hund- Platz 1, 37077 Göttingen
Soft X-ray imaging with high amplitude contrast in the water window regime (2.3 - 4.4 nm) has become an established technique for in-vivo investigation of biological structures e.g. in cytology. For soft X-ray wavelength all materials have a refractive index n close to 1, so that significant refraction cannot be accomplished by conventional lenses. Therefore multilayer interference coatings formed by depositing alternating layers of two materials of differing refractive index are applied as optical elements. Requirements for optimal film reflectance are a high difference in absorption coefficient as well as high quality interfaces. For this purpose, MgO/Ti and ZrO2/Ti multilayers with double layer periods in the nanometer range were deposited by pulsed laser deposition (PLD) on Si(111) substrates in ultrahigh vacuum. The interface structures were studied by X-ray reflectometry (XRR), transmission electron microscopy (TEM) and in-situ stress measurements. In this contribution, the underlying growth processes and their influence on the interface roughnesses are presented.